Influence of the cold plasma treatment on the Al2O3/ZrO2 nanocomposites surfaces

Abstract

In the present work, Al2O3/ZrO2 nanocomposite surfaces were treated with cold plasma using N2,H2, andO2 gaseous atmospheres. For this, Al2O3/ZrO2 samples were shaped and sintered at 1500 °C for 2 h. Then, the surfaces were treated with cold plasma using different N2 and O2 gas flow proportions. The H2 gas flow was maintained at 50%. The treatment conditions were a total gas flow rate of 20 sccm, total pressure of 2.0 mbar, square pulses of voltage with duration of the 50 µs repeated every 100 µs, and a temperature of 400 °C. The surface treatment, regardless of the gaseous atmospheres, affected the functional groups attributed to ZrO2 significantly more than those of Al2O3. In general, it was observed that the surfaces treated in gaseous atmospheres with a higher proportion of N2 gas flow had a more hydrophilic character due to the greater amount of active species coming from this gas. Although active N2 gas species are predominant, active O2 gas species can also affect ZrO2 functional groups. Thus, the pre-treatment contributes both to increasing hydrophilic character as well as promoting chemical changes in the functional groups present on the nanocomposite surfaces.